Engine problems, hesitation

[deloumis]

Im having some trouble trying to get my engine running right. As I stated on my post about my transmission problem, my car had been sitting for quite some time when i purchased it. Now trying to get it running right.

When I fiirst go to start my car it always starts right away, but dies out right away. Then I crank her up again and it will take about 2-3 seconds then will start. The idle will be really rough for the first 15-20 seconds the will smooth out. When the idle is finally smooth the car hesitates to increase rev up. On the road the car has no power. The only thing that seems to smooth out the idle and help with hesitation is when I richen the mixture with the mixture screw. The only problem when i do that is my idle stays up at 1500.

Am I running too lean? How do I bring down the idle?

Thanks in advance!

[WelmoedJ]

Im having some trouble trying to get my engine running right. As I stated on my post about my transmission problem, my car had been sitting for quite some time when i purchased it. Now trying to get it running right.

If it has been sitting long time, the remainig gas in the fuel tank starts to deteriorate.
It becomes gumlike and when you fill the tank with fresh fuel, the old fuel remains will dissolve and get into the fuel system.

- So question 1 is: did you clean the fuel tank and system (accumulator, filter, distributor, CPR, injectors) before trying to start the car?


When I first go to start my car it always starts right away, but dies out right away. Then I crank her up again and it will take about 2-3 seconds then will start. The idle will be really rough for the first 15-20 seconds the will smooth out. When the idle is finally smooth the car hesitates to increase rev up.

This seems to me a typical example of fuel supply problems: clean the system!


On the road the car has no power. The only thing that seems to smooth out the idle and help with hesitation is when I richen the mixture with the mixture screw. The only problem when i do that is my idle stays up at 1500.
Am I running too lean? How do I bring down the idle?.

You need to check the entire fuel system, prior to starting adjusting the mixture.
You may have leaking or not well working injectors (no or wrong spray pattern).
This all influences proper behavior. Too rich floods the cylinders and is contra productive.
Also try swapping the grey and bleu connectors before cold starting. If that helps, see question 1.
Check for vacuum leaks as they also influence proper running.
Did you replace the air filter? A clogged air filter is keeping your car from getting air resulting in less to bad performance.
Loss of power can be the resultant of all of this.

[Spittybug]

Welmoed is absolutely right. If you are fiddling with settings before having done a top to bottom cleaning of the fuel system, you are likely to be fighting this for a very long time and at significant expense.

[David T]

You will NEVER "fix" problems by messing with the mixture adjustment. You must go over the fuel system and make it run 100% correctly BEFORE attempting to adjust the mixture screw. Your problem is one or more of the following:
Bad fuel
Vacuum leaks
Dirty injectors
Sticking plunger
Bad CPR
Start by cleaning out the fuel tank. BTW, are you pluging the hole over the mixture screw after you mess with it? If you don't it will be a BIG vacuum leak!
David Teitelbaum

[deloumis]

If it has been sitting long time, the remainig gas in the fuel tank starts to deteriorate.
It becomes gumlike and when you fill the tank with fresh fuel, the old fuel remains will dissolve and get into the fuel system.

- So question 1 is: did you clean the fuel tank and system (accumulator, filter, distributor, CPR, injectors) before trying to start the car?



This seems to me a typical example of fuel supply problems: clean the system!



You need to check the entire fuel system, prior to starting adjusting the mixture.
You may have leaking or not well working injectors (no or wrong spray pattern).
This all influences proper behavior. Too rich floods the cylinders and is contra productive.
Also try swapping the grey and bleu connectors before cold starting. If that helps, see question 1.
Check for vacuum leaks as they also influence proper running.
Did you replace the air filter? A clogged air filter is keeping your car from getting air resulting in less to bad performance.
Loss of power can be the resultant of all of this.

The first thing I did was removed the tank and completely clean it out. I replaced the fuel pump and fuel filter. I removed the fuel distributor and took it apart, cleaned it, and replaced the o rings. The CPR I also removed, opened up and cleaned. I replaced the fuel filter 2 times (I'm on my 3rd filter). Injectors are all new. The only thing I have not messed with is the accumulator. I have read up that it can cause problems, but I'm not sure if the problems I am experiencing can be caused by it.

The injectors have a good pattern. They have been checked plenty of times. I had vacuum leaks, but were all fixed. Air filter is also new.

Thanks and I hope this information helps to diagnose the problem.


Welmoed is absolutely right. If you are fiddling with settings before having done a top to bottom cleaning of the fuel system, you are likely to be fighting this for a very long time and at significant expense.

I am almost completely sure that my fuel system is completely clean. Many components have been taken apart and cleaned or replaced. Injectors are new, CPR, FD, CSV and Fuel Tank have all been taken apart and cleaned. I may be missing one small component that is keeping my engine from running correct, I just cannot come up with the solution.


You will NEVER "fix" problems by messing with the mixture adjustment. You must go over the fuel system and make it run 100% correctly BEFORE attempting to adjust the mixture screw. Your problem is one or more of the following:
Bad fuel
Vacuum leaks
Dirty injectors
Sticking plunger
Bad CPR
Start by cleaning out the fuel tank. BTW, are you pluging the hole over the mixture screw after you mess with it? If you don't it will be a BIG vacuum leak!
David Teitelbaum

Bad Fuel is out of the question, tank was completely cleaned out along with alot of components.
Vacuum leaks were all fixed and I went over again and again searching for more but came up with nothing. (possible I still have a small vacuum leak I didn't find, but I doubt it.)
Injectors are all new
Plunger seems ok.
How would I check CPR? I cleaned it and I have even swapped out for another I have but made no noticeable difference.

I have already cleaned out the fuel tank, and yes I do cover up the hole.

At the moment, the engine seems to be running OK, but it is still not perfect, and I cannot bring the idle down any further than 1300.

I hope this info helps!

[WelmoedJ]

- If the fuel accumulator is bad, it may cause problems: it can obstruct the flow, it can influence start

- Did you by any chance mess with the distributor's timing? Is the vacuum advance working properly (connected)?

- Did you also check the vacuum lines to the front of the car (brake booster, centre console selector, valves of the heater & A/C doors)?

- Does your car still have the original catalytic converter? It's interior may have broken up thus blocking up or restricting the pasage for the exhaust gases?

- Is your auxiliary air pipe mounted correctly (high idle sometimes also is the result of vacuum leaks)?

- As your car is an automatic, how about the vacuum regulator and it's connections?

- By "rough idle" do you mean "hunting" Revving up and down? That usually is a sign of too rich a mixture.

- If you use the accelarator to rev the engine, does it quickly return to normal when releasing the accellerator? If this is not following the pedal, you also may have a distributor with a slightly sticking plunger. It should move freely up and down.

- You mention having been fiddling with the fuel mixture. You may want to set the mixture screw to the best possible mixture. I'm not sure I recall the "reset" procedure correctly, but I think you should turn it all the way counter clockwise until you can't turn it no more, then turn clockwise some three full turns. This should bring you about right for starters.
If this is not correct, professors, please chime in.

[deloumis]

- If the fuel accumulator is bad, it may cause problems: it can obstruct the flow, it can influence start

- Did you by any chance mess with the distributor's timing? Is the vacuum advance working properly (connected)?

- Did you also check the vacuum lines to the front of the car (brake booster, centre console selector, valves of the heater & A/C doors)?

- Does your car still have the original catalytic converter? It's interior may have broken up thus blocking up or restricting the pasage for the exhaust gases?

- Is your auxiliary air pipe mounted correctly (high idle sometimes also is the result of vacuum leaks)?

- As your car is an automatic, how about the vacuum regulator and it's connections?

- By "rough idle" do you mean "hunting" Revving up and down? That usually is a sign of too rich a mixture.

- If you use the accelarator to rev the engine, does it quickly return to normal when releasing the accellerator? If this is not following the pedal, you also may have a distributor with a slightly sticking plunger. It should move freely up and down.

- You mention having been fiddling with the fuel mixture. You may want to set the mixture screw to the best possible mixture. I'm not sure I recall the "reset" procedure correctly, but I think you should turn it all the way counter clockwise until you can't turn it no more, then turn clockwise some three full turns. This should bring you about right for starters.
If this is not correct, professors, please chime in.

I did mess with the timing but i have set it to where it should be. The vacuum advance is working, I disconnect and it makes a noticeable difference.

The vacuum which goes up front may have come undone. My AC isn't working properly, will not change vents. It was but stopped. Where is this line located? I tried looking but couldn't fine it.

No I have DPIs exhaust with headers, dual cats.

Auxiliary air pipe? Which would that be? Where is the vacuum regulator located for the auto transmission?

By rough I meant no power, if I try to give it gas it seems as if it wants to die. The only time I experience idle hunting is when i try to bring the idle down. If I try to bring it down any lower than it is now, it will hunt between about 800-1300

I can reset the mixture, but I just need help on the best and proper way to do it and have it set right

[WelmoedJ]

I did mess with the timing but i have set it to where it should be. The vacuum advance is working, I disconnect and it makes a noticeable difference.
Okay, we let this as is.


The vacuum which goes up front may have come undone. My AC isn't working properly, will not change vents. It was but stopped. Where is this line located? I tried looking but couldn't fine it.
There is a plastic tube running underneath the centre console at the drivers side.
It is connected to a soft rubber hose that goes to the selector and from there to the various doors of the ventilation system. It may be the hoses, it may be the rubber diafragm in the selector, it may be the valves at the doors that could leak. Check them all.


No I have DPIs exhaust with headers, dual cats.
Then they are rather new and probably above suspicion.


Auxiliary air pipe? Which would that be? Where is the vacuum regulator located for the auto transmission?
From the Idle Speed Motor a brass tube runs to the mixture unit. At the entrance it's sealed with an O-ring.
Very often this O-ring is not seated correctly or entirely missing.
The vacuum regulator is situated at the left side of the tranny.


By rough I meant no power, if I try to give it gas it seems as if it wants to die. The only time I experience idle hunting is when i try to bring the idle down. If I try to bring it down any lower than it is now, it will hunt between about 800-1300
Upon cold start, if the mixture is rich and your cold start valve is leaking this could also cause your engine to almost have no power (kind of starving of too much "food"), seems to die, but actually drowns in fuel.
If at cold start after the engine is idling you remove the electrical plug of the idle speed motor, does that change idle behavior?
If at cold start you lean out the mixture more (like 5 minute steps) would this also stop hunting? A properly idling engine should not hunt, if and only if all is correct (vacuum not leaking, parts working properly (especially CPR, idle switch/ISM etc).
Rounds should be at some 750-850 ideally.


I can reset the mixture, but I just need help on the best and proper way to do it and have it set right
Call Dave Swingle and ask if my described way (previously message) is the way to go.
As I said, I'm not 100 sure, that's why I invited other owners to chime in.

[robvanderveer]

perhaps related story: my car failed to accelerate until i changed injectors.

When I stepped on the throttle, the car used to stall, i needed to less back on the gas and accelerate slowly. It turned out I had a bad injector (probably clogged). The bad injector caused fuel to fill up during idle in the chamber, causing misfires and backfires. After a backfire (usually right after putting my foot down) had cleaned the the chamber, it would usually run better for a while.

[deloumis]

I had some time yesterday to mess with the car, but u still can't find the problem. To this day I have don't quite a few things. I cleaned all fuel components except accumulator, replaced injectors, plugs, and wires, cleaned cap and rotor, replaced coil, replaced 02 sensor, replaced all relays, searched and fixed vacuum leaks, and done just about all I know I can do. The car starts and runs but no power whatsoever.

I had initially thought it was a fuel problem, seems as if it is lacking fuel. One test I did (not sure if it is safe to do) was put the grey plug on the CSV. The car drove like a champ that way. Had power and actually moved the car the way it should. But if I turn up the fuel any more than it is, it will flood the engine.

I have no clue what I might have missed, or what the problem could be so I can look over again.

Any help or input is appreciated

[Bitsyncmaster]

I assume you have adjusted the FV duty cycle (dwell). My guess is your FD has a problem since you have replaced most everything. I would suggest you pull all six injectors and get six jars. Then you jumper the RPM relay and press the air plate down about half way. Hold that until the jars are about half full. Then compare the amount in each jar.

[deloumis]

I assume you have adjusted the FV duty cycle (dwell). My guess is your FD has a problem since you have replaced most everything. I would suggest you pull all six injectors and get six jars. Then you jumper the RPM relay and press the air plate down about half way. Hold that until the jars are about half full. Then compare the amount in each jar.

How do you adjust the cycle? I have not done it, or at least I don't think so. My FD was opened up and cleaned, along with replacing o rings. But I can still try and see what it does.

[Bitsyncmaster]

How do you adjust the cycle? I have not done it, or at least I don't think so. My FD was opened up and cleaned, along with replacing o rings. But I can still try and see what it does.

You need a meter that reads dwell or duty cycle. I attach that meter to the orange wire on the two pin connector from the engine harness going to the diagnostic plug. You adjust the reading via the FD mixture adjustment screw.

[David T]

Is the frequency valve buzzing? If it isn't you wind up setting the fuel mixture way too rich to compensate for the FV not running. The motor seems like it is running way too rich but it won't accelerate because it leans out as you increase RPM's. Once you know the FV is working you can put a dwell meter on and check (and adjust if necessary) the duty cycle.
David Teitelbaum

[Delorean Industries]

Something needs to be done about this user name/who you are situation on here. I have no idea who this could be and you are running our exhaust. Always available to help at [email protected]

-Josh

[DMCMW Dave]

My FD was opened up and cleaned, along with replacing o rings. But I can still try and see what it does.

By whom? This is not often successful with zero experience, if you did it yourself this is probably the real problem.

[deloumis]

Something needs to be done about this user name/who you are situation on here. I have no idea who this could be and you are running our exhaust. Always available to help at [email protected]

-Josh

My dad bought me the exhaust for Christmas, my dad is Levy on this board.

[deloumis]

Is the frequency valve buzzing? If it isn't you wind up setting the fuel mixture way too rich to compensate for the FV not running. The motor seems like it is running way too rich but it won't accelerate because it leans out as you increase RPM's. Once you know the FV is working you can put a dwell meter on and check (and adjust if necessary) the duty cycle.
David Teitelbaum

Yes it is, or at least was. I will check again. I had a dead battery today so I wasn't able to do anything today.

[deloumis]

You need a meter that reads dwell or duty cycle. I attach that meter to the orange wire on the two pin connector from the engine harness going to the diagnostic plug. You adjust the reading via the FD mixture adjustment screw.

I will need to buy me a dwell meter, I do not own one. When I do i will check, what should it be at?

[deloumis]

By whom? This is not often successful with zero experience, if you did it yourself this is probably the real problem.

I have 2 complete FDs, the first problem I had was the return line was clogged so all the o rings blew on both of them. With the help of a member on here, my dad was able to figure this out. My dad was the one to open them up and repair them. He is really good at fixing things, and has pretty good experience with many other vehicles. I'm not saying its not the problem, it could be, but I have alot of confidence on my dads work.

How can I test it to find if it is the problem?

[Bitsyncmaster]

When you get the meter, press the WOT after the engine has warmed up and you should read 60%. That will show you your meter is working and so is your lambda. Then with a warmed up engine, adjust the mixture to read about 30-40% at idle. You should see it swinging around those values so an exact setting is not critical. Then you have the proper average mixture.

Note I said average since the lambda system reads the mixture on all six cylinders. So if one or more cylinders is getting more or less fuel than the others it will upset the lambda setting the proper mixture.

[Bitsyncmaster]

Use the book for dwell numbers. But I like using duty cycle since you don't have to set the number of cylinders. When you use the book values of dwell you need to set your meter to 4 cylinders. Dwell for 4 cylinder reads from 0 to 90 degrees. Duty cylcle always read from 0 to 100%. So duty cylcle number are 10% higher than dwell numbers.

[WelmoedJ]

I had initially thought it was a fuel problem, seems as if it is lacking fuel. One test I did (not sure if it is safe to do) was put the grey plug on the CSV. The car drove like a champ that way. Had power and actually moved the car the way it should. But if I turn up the fuel any more than it is, it will flood the engine.


I noticed nobody commenting on this.
The grey plug is supposed to be on the CPR at all times.
Although it's the also called WUR (aiding in cold start) it is part of the fuel system regulation and should be kept in the loop.

I also noticed you telling that your father took the FD apart.
Did he take precautions while disassembling to make sure he knows the original position (chamber) the springs and belonging shims came from and thus have to be placed in while rebuilding?

Did he also make sure the surface of the metal membrane was smooth as a baby's butt so it would not leak after completing the rebuild?

My two cents.

[Delorean Industries]

My dad bought me the exhaust for Christmas, my dad is Levy on this board.

Ahhh! That explains it. I do my best to match all of our customer files with user names on here and I was drawing a blank!

[deloumis]

When you get the meter, press the WOT after the engine has warmed up and you should read 60%. That will show you your meter is working and so is your lambda. Then with a warmed up engine, adjust the mixture to read about 30-40% at idle. You should see it swinging around those values so an exact setting is not critical. Then you have the proper average mixture.

Note I said average since the lambda system reads the mixture on all six cylinders. So if one or more cylinders is getting more or less fuel than the others it will upset the lambda setting the proper mixture.

I will likely get the dwell meter this week, so when I do I will be are to do this and report back.



I noticed nobody commenting on this.
The grey plug is supposed to be on the CPR at all times.
Although it's the also called WUR (aiding in cold start) it is part of the fuel system regulation and should be kept in the loop.

I also noticed you telling that your father took the FD apart.
Did he take precautions while disassembling to make sure he knows the original position (chamber) the springs and belonging shims came from and thus have to be placed in while rebuilding?

Did he also make sure the surface of the metal membrane was smooth as a baby's butt so it would not leak after completing the rebuild?

My two cents.

I do understand the grey plug should be on the CPR at all times. I also understand that by plugging it into the CSV I had a constant sho of extra fuel. This is the point I was trying to get across. With it plugged where it should go, the car does not run good at all. The cat will start but will not move easily. Pushing down on the gas would result in the car wanting to die. But the one time I switched the lug and went for a spin, the car ran awesome, like a champ! I just wish it would run that way all the time. The reason I did this was because last week I was able go get my car running almost perfect. The reason it did run so good was because I had adjusted the mixture screw to run with alot more fuel. The problem was that now I was flooding the engine so I turned it back down.


Ahhh! That explains it. I do my best to match all of our customer files with user names on here and I was drawing a blank!

Sorry for the confusion, but I hope now you know who I am. BTW I loved the exhaust, I just ended up with a small leak I have to fix. I believe it is the gasket from headers to head.

[WelmoedJ]

I do understand the grey plug should be on the CPR at all times. I also understand that by plugging it into the CSV I had a constant sho of extra fuel.
This only works if you have starting problems and the switch should be reversed once started.


This is the point I was trying to get across. With it plugged where it should go, the car does not run good at all. The cat will start but will not move easily. Pushing down on the gas would result in the car wanting to die.
That can happen with too little or too much fuel.
What happen if it seems to die and you get off of the accelerator? Does it come back to "life"?


But the one time I switched the lug and went for a spin, the car ran awesome, like a champ! I just wish it would run that way all the time. The reason I did this was because last week I was able go get my car running almost perfect. The reason it did run so good was because I had adjusted the mixture screw to run with alot more fuel. The problem was that now I was flooding the engine so I turned it back down.
Proofs part of my previous remark.

Anyway you should do all the tests advised (Bitsyncmaster and others).
Besides that: you didn't comment on the remark about the FD rebuild.
Can you give details?

[DMCMW Dave]

Besides that: you didn't comment on the remark about the FD rebuild.
Can you give details?

I agree, and I'd still bet that he ends up replacing the fuel distributor (again). If he messed around with the shims or the metal plate isn't flat, it's not gonna work.

[deloumis]

I'm not sure exactly what or howitzers was done.. but I will do what was told and see what happens.

[WelmoedJ]

If you have to replace the FD - because of the mentioned membrane defects - I would advice to go and look for a Renault FD. That type has adjustment screws for each of the chambers.
That avoids the need of opening and putting in shims to resolve differences in fuel quantities between chambers.

The Renault FDs are easily recognized by the extra screw mounts aside each of the fuel line openings.

[Bitsyncmaster]

If you have to replace the FD - because of the mentioned membrane defects - I would advice to go and look for a Renault FD. That type has adjustment screws for each of the chambers.
That avoids the need of opening and putting in shims to resolve differences in fuel quantities between chambers.

The Renault FDs are easily recognized by the extra screw mounts aside each of the fuel line openings.

+1

I have this FD also and I measured and adjusted my FD for equall flow on all six injectors.

[deloumis]

If you have to replace the FD - because of the mentioned membrane defects - I would advice to go and look for a Renault FD. That type has adjustment screws for each of the chambers.
That avoids the need of opening and putting in shims to resolve differences in fuel quantities between chambers.

The Renault FDs are easily recognized by the extra screw mounts aside each of the fuel line openings.

Where can I find one of these, and what is the price?
How much does it cost to have my FD rebuilt?

[jawn101]

Where can I find one of these, and what is the price?
How much does it cost to have my FD rebuilt?

Both Hervey and Houston offer rebuilt units with a core charge (FD only, no mixture control unit) for around $500. Original DeLorean ones, not the Renault one mentioned above. I'm sure the other affiliates do as well so go with who you like :)

I've not seen those Renault FDs for sale before but am also now curious.

[Delorean Industries]

We have the best deal around on rebuilt fuel distributors. Contact us at 330 573 4129 or [email protected] for rebuild options.

[WelmoedJ]

Where can I find one of these, and what is the price?
How much does it cost to have my FD rebuilt?

Usually they are not found at the DMC service stations as they are specifically for Renault vehicles.
If you're interested, Martin G with DeLorean UK sometimes has them, otherwise it's looking for junkyards that have European cars, searching the internet and e-bay.

Mind that there are two versions: one in metal and one in aluminium. You go for the all metal version. If the bottom part is not alike the bottom part of the standard FD, no problem.
The Renault top (only from the all metal version) will fit the standard FD bottom.
In case you have to do the "top exchange", be careful with the membrane otherwise you will end up with the same trouble you now have.

You may want to visit Hervey's fuel distributor page http://specialtauto.com/fuel-distributors.html where you also will find a rebuilt DeLorean FD that has the Renault adjusting screws (ref: Bosch 0-438-100-109A). No bother to do exchanges but at a price. It's your call now.

[Bitsyncmaster]

I will check the part number on mine just to verify. But I think these Renalt ones sell for less the our OEM units.